What does the F in F7 or F8 in ventilation filters mean

Air Filter Element: A filter unit to clean air from particulate contamination comprising filter material including framing, supporting parts and gaskets, the total to be inserted into a filter housing device.

Performance Data: Single values out of the filter test report as carried out in accordance with EN 779:2012.

Filter family: A filter family is characterised by the following:

the same filter material
the same basic construction (e.g. bag, V-type, etc.)
the same face velocity : rated air-flow / min. net filter area; (does not have to be published). The airflow rate shall be adapted to the face area.
The same length/depth of the overall filter element with a tolerance of +/- 10% or 50 mm whatever is the smaller
The same ratio of filter medium area to front face area
the same filter class M5, M6, F7, F8 or F9
published data available about: basic construction, filter media, filter class available via internet or other published sales brochures.
Representative Filter Element: Any type chosen by Eurovent Certita Certification out of a “filter” fitting into the EN 779 – test rig.

F-Filter Class: Class of fine (group “F”) air filters based on classification according to EN 779:2012 (F7, F8 or F9).

M-Filter Class: Class of medium (group “M”) air filters based on classification according to EN 779:2012 (M5, M6).

Initial Pressure Drop: Pressure drop of the clean filter operating at the test air flow rate.

Initial Efficiency: Efficiency of the clean filter operating at the test air flow rate.

Discharged Efficiency: Discharged efficiency of media at 0.4 µm according to EN 779:2012 clause 11.

Minimum Efficiency: Lowest efficiency among the discharged efficiency, initial efficiency and the lowest efficiency throughout the loading procedure of the test – Note: Minimum efficiency is used for the classification of F-filters (see definition in EN779:2012).

Eurovent Energy Efficiency Class: Energy Efficiency class as defined in RS 4/C/001-2015.

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